I could see something in the 30k capacity area making sense. Personally, I would do something just north of the Franklin Station. A design like McMahon could work with the 1 end being very open and placed correctly would offer a great skyline view (though may be bad for wind). If engineered correctly, noise to the residential areas in the south could be minimized and directly west, north and east likely don't care much. That would allow for more concerts/music festivals to make the facility a little more viable. Perhaps Cavalry too, as I recall reading a while ago that MLS was an aspiration for the club.
Additionally, I feel like the industrial area North of Memorial between Barlow and 36th could be prime for residential. Starting around a new stadium and moving North to 16 Ave. Much of the area is close to LRT, as the line turns north on 36th. This is likely a 50 year project, but with quick access to DT and suburban amenities along 36 Street, it's almost the best of both worlds and I could see there being demand for housing. If someone proposed a building with 25 floors at Centre Ave and 28 St today, I can't imagine the opposition would be very high and that that exists wouldn't be credible.
Barlow and 36 St. Probably never change, but the middle area could be good over the very long term with a stadium as an anchor.